The proliferation of configurable electronic devices continues to expand. The development of system in package (SIP) devices has advanced the development of smartphones, tablet computers, robotic applications, vending machines, and much more. The combination of functions within a SIP can be problematic as the electrical and timing requirements of the combined functions can be different.
As SIP applications are expanding, problems arise due to difficulties in initialization of these devices. A careful coordination of the initialization timing within the SIP can create extremely difficult problems to solve in the field. In some extreme cases, the flexibility of the SIP is limited by the configuration required to perform the initialization calibration.
Almost all integrated circuits (ICs) contain some analog/mixed-signal blocks. These typically require a constant current and voltage reference for biasing. While the voltage reference is usually implemented with an on-chip band gap reference (BGR), the current reference typically needs an External Precision Resistor (EPR), which has less than 1% variation. The situation becomes complicated if there are multiple chips in an SIP and each needs its own EPR. For an SIP with multiple chips, multiple EPRs are required, increasing ball count and system cost.
The configuration can be much more complicated when the control device is implemented by a field programmable gate array (FPGA), which itself has a complicated initialization process. The inclusion of an FPGA, as the control device in an electronic system, can cause the initialization process to become complicated and unwieldy.
Thus, a need still remains for an integrated circuit system with external resistors. In view of the ever-increasing commercial competitive pressures, along with growing consumer expectations, it is critical that answers be found for these problems. Additionally, the need to reduce costs, improve efficiencies and performance, and meet competitive pressures adds an even greater urgency to the critical necessity for finding answers to these problems.